The first frame of the animation shows where the bird can find a suitable climate today (based on data from 2000). The next three frames predict where this bird’s suitable climate may shift in the future—one frame each for 2020, 2050, and 2080.

This West Coast alcid is common, but generally seen well out at sea, and thus little known to most birders. Studies suggest its movements relate to changes in sea surface temperature, which can affect food availability. Research also suggests that short-term population fluctuations are connected to El Niño–La Niña phenomena. Audubon's climate model forecasts a substantial increase in the amount of climatically suitable areas for wintering birds, but only 17% of the current range remains stable. Unsurprisingly, much of this increase is predicted to be in the north. The key with the Cassin’s Auklet, and indeed with most if not all alcids, isn’t climate per se—these birds are hardy! Rather, it is whether their climatically sensitive prey will be able to adapt to and flourish in a changing climate, and whether the oceanic islands it needs for nesting will be in the new climate space.

Species Range Change from 2000 to 2080

The size of the circles roughly indicates the species’ range size in 2000 (left) and 2080 (right).

The amount of overlap between the 2000 circle and the 2080 circle indicates how stable the range will be geographically. Lots of overlap means the bird’s range doesn’t shift much. No overlap means the species will leave its current range entirely.